1. Field of the Invention
The present disclosure generally relates to display techniques, and particularly relates to a compensation circuit and an organic light emitting diode display device.
2. The Related Arts
Active Matrix Organic Light Emitting Diode (AMOLED) is a new display and lighting technique that controls currents flowing through the LEDs by Thin Film Transistor (TFT) drivers. The TFTs' threshold voltages may shift due to factors such as light illumination, stress, the voltage between source and drain, etc., causing the threshold voltages to shift, affecting the currents flowing through the LEDs, and leading to un-uniform display.
Existing solutions try to resolve the shift of the driver TFTs' threshold voltages by compensation. A Reset stage of the compensation process resets the gate and source voltages of the driver TFTs by charging a capacitor through a reset initialization signal Vini so that driver TFTs' gate and source voltages are reset to Vini. In reality, however, there is only limited time for the Reset stage. In the meantime, the driver TFTs' cut off condition VGL−Vini<Vth has to be satisfied, where Vth is the threshold voltage of the driver TFTs. As such, the reset initialization signal Vini cannot be too low. This leads to that the capacitor is not fully charged during the Reset stage, and the gate and source voltages of the driver TFTs do not reach the preset level Vini. The compensation effect is therefore compromised. An improved design capable of reducing capacitor charging time and enhancing Reset efficiency is desired.